1. Field of the Invention
The present invention generally relates to a method of forming an insulation film by pulse plasma chemical vapor deposition (pulse CVD) or atomic layer deposition (ALD).
2. Description of the Related Art
SiN films used as gate spacers must offer a good coverage and have an etch rate equivalent to or less than thermal oxide films. A general rule of thumb is that the lower the film forming temperature, the better the coverage. However, films formed at low temperature present a problem in that they have a very high wet etching rate (WER). For example, a sequence based on the conventional pulse CVD is shown in FIG. 1(a). A similar pattern is also seen when ALD is used.